package com.mindata.blockchain.core.sqlite.config;

import java.sql.SQLException;
import java.sql.Types;

import org.hibernate.JDBCException;
import org.hibernate.ScrollMode;
import org.hibernate.dialect.Dialect;
import org.hibernate.dialect.function.AbstractAnsiTrimEmulationFunction;
import org.hibernate.dialect.function.NoArgSQLFunction;
import org.hibernate.dialect.function.SQLFunction;
import org.hibernate.dialect.function.SQLFunctionTemplate;
import org.hibernate.dialect.function.StandardSQLFunction;
import org.hibernate.dialect.function.VarArgsSQLFunction;
import org.hibernate.dialect.identity.IdentityColumnSupport;
import org.hibernate.dialect.pagination.AbstractLimitHandler;
import org.hibernate.dialect.pagination.LimitHandler;
import org.hibernate.dialect.pagination.LimitHelper;
import org.hibernate.dialect.unique.DefaultUniqueDelegate;
import org.hibernate.dialect.unique.UniqueDelegate;
import org.hibernate.engine.spi.RowSelection;
import org.hibernate.exception.DataException;
import org.hibernate.exception.JDBCConnectionException;
import org.hibernate.exception.LockAcquisitionException;
import org.hibernate.exception.spi.SQLExceptionConversionDelegate;
import org.hibernate.exception.spi.TemplatedViolatedConstraintNameExtracter;
import org.hibernate.exception.spi.ViolatedConstraintNameExtracter;
import org.hibernate.internal.util.JdbcExceptionHelper;
import org.hibernate.mapping.Column;
import org.hibernate.type.StandardBasicTypes;

import com.mindata.blockchain.core.sqlite.config.identity.SQLiteDialectIdentityColumnSupport;

/**
 * sqlite方言，目的是使用Hibernate jpa操作SQLite
 * 
 * @author wuweifeng wrote on 2018/3/2.
 */
public class SQLiteDialect extends Dialect {
	private final UniqueDelegate uniqueDelegate;

	public SQLiteDialect() {
		registerColumnType(Types.BIT, "boolean");
		//registerColumnType(Types.FLOAT, "float");
		//registerColumnType(Types.DOUBLE, "double");
		registerColumnType(Types.DECIMAL, "decimal");
		registerColumnType(Types.CHAR, "char");
		registerColumnType(Types.LONGVARCHAR, "longvarchar");
		registerColumnType(Types.TIMESTAMP, "datetime");
		registerColumnType(Types.BINARY, "blob");
		registerColumnType(Types.VARBINARY, "blob");
		registerColumnType(Types.LONGVARBINARY, "blob");

		registerFunction("concat", new VarArgsSQLFunction(StandardBasicTypes.STRING, "", "||", ""));
		registerFunction("mod", new SQLFunctionTemplate(StandardBasicTypes.INTEGER, "?1 % ?2"));
		registerFunction("quote", new StandardSQLFunction("quote", StandardBasicTypes.STRING));
		registerFunction("random", new NoArgSQLFunction("random", StandardBasicTypes.INTEGER));
		registerFunction("round", new StandardSQLFunction("round"));
		registerFunction("substr", new StandardSQLFunction("substr", StandardBasicTypes.STRING));
		registerFunction("trim", new AbstractAnsiTrimEmulationFunction() {
			@Override
			protected SQLFunction resolveBothSpaceTrimFunction() {
				return new SQLFunctionTemplate(StandardBasicTypes.STRING, "trim(?1)");
			}

			@Override
			protected SQLFunction resolveBothSpaceTrimFromFunction() {
				return new SQLFunctionTemplate(StandardBasicTypes.STRING, "trim(?2)");
			}

			@Override
			protected SQLFunction resolveLeadingSpaceTrimFunction() {
				return new SQLFunctionTemplate(StandardBasicTypes.STRING, "ltrim(?1)");
			}

			@Override
			protected SQLFunction resolveTrailingSpaceTrimFunction() {
				return new SQLFunctionTemplate(StandardBasicTypes.STRING, "rtrim(?1)");
			}

			@Override
			protected SQLFunction resolveBothTrimFunction() {
				return new SQLFunctionTemplate(StandardBasicTypes.STRING, "trim(?1, ?2)");
			}

			@Override
			protected SQLFunction resolveLeadingTrimFunction() {
				return new SQLFunctionTemplate(StandardBasicTypes.STRING, "ltrim(?1, ?2)");
			}

			@Override
			protected SQLFunction resolveTrailingTrimFunction() {
				return new SQLFunctionTemplate(StandardBasicTypes.STRING, "rtrim(?1, ?2)");
			}
		});
		uniqueDelegate = new SQLiteUniqueDelegate(this);
	}

	// database type mapping support ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

	/*
	 * @Override public String getCastTypeName(int code) { // http://sqlite.org/lang_expr.html#castexpr return
	 * super.getCastTypeName( code ); }
	 */

	// IDENTITY support ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

	private static final SQLiteDialectIdentityColumnSupport IDENTITY_COLUMN_SUPPORT = new SQLiteDialectIdentityColumnSupport(
			new SQLiteDialect());

	@Override
	public IdentityColumnSupport getIdentityColumnSupport() {
		return SQLiteDialect.IDENTITY_COLUMN_SUPPORT;
	}

	// limit/offset support ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
	private static final AbstractLimitHandler LIMIT_HANDLER = new AbstractLimitHandler() {
		@Override
		public String processSql(final String sql, final RowSelection selection) {
			final boolean hasOffset = LimitHelper.hasFirstRow(selection);
			return sql + (hasOffset ? " limit ? offset ?" : " limit ?");
		}

		@Override
		public boolean supportsLimit() {
			return true;
		}

		@Override
		public boolean bindLimitParametersInReverseOrder() {
			return true;
		}
	};

	@Override
	public LimitHandler getLimitHandler() {
		return SQLiteDialect.LIMIT_HANDLER;
	}

	// lock acquisition support ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
	@Override
	public boolean supportsLockTimeouts() {
		// may be http://sqlite.org/c3ref/db_mutex.html ?
		return false;
	}

	@Override
	public String getForUpdateString() {
		return "";
	}

	@Override
	public boolean supportsOuterJoinForUpdate() {
		return false;
	}

	// current timestamp support ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

	@Override
	public boolean supportsCurrentTimestampSelection() {
		return true;
	}

	@Override
	public boolean isCurrentTimestampSelectStringCallable() {
		return false;
	}

	@Override
	public String getCurrentTimestampSelectString() {
		return "select current_timestamp";
	}

	// SQLException support ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

	private static final int SQLITE_BUSY = 5;
	private static final int SQLITE_LOCKED = 6;
	private static final int SQLITE_IOERR = 10;
	private static final int SQLITE_PROTOCOL = 15;
	private static final int SQLITE_TOOBIG = 18;
	private static final int SQLITE_CONSTRAINT = 19;
	private static final int SQLITE_MISMATCH = 20;
	private static final int SQLITE_NOTADB = 26;

	@Override
	public SQLExceptionConversionDelegate buildSQLExceptionConversionDelegate() {
		return new SQLExceptionConversionDelegate() {
			@Override
			public JDBCException convert(final SQLException sqlException, final String message, final String sql) {
				final int errorCode = JdbcExceptionHelper.extractErrorCode(sqlException) & 0xFF;
				if (errorCode == SQLiteDialect.SQLITE_TOOBIG || errorCode == SQLiteDialect.SQLITE_MISMATCH) {
					return new DataException(message, sqlException, sql);
				} else if (errorCode == SQLiteDialect.SQLITE_BUSY || errorCode == SQLiteDialect.SQLITE_LOCKED) {
					return new LockAcquisitionException(message, sqlException, sql);
				} else if ((errorCode >= SQLiteDialect.SQLITE_IOERR && errorCode <= SQLiteDialect.SQLITE_PROTOCOL)
						|| errorCode == SQLiteDialect.SQLITE_NOTADB) {
					return new JDBCConnectionException(message, sqlException, sql);
				}

				// returning null allows other delegates to operate
				return null;
			}
		};
	}

	@Override
	public ViolatedConstraintNameExtracter getViolatedConstraintNameExtracter() {
		return SQLiteDialect.EXTRACTER;
	}

	private static final ViolatedConstraintNameExtracter EXTRACTER = new TemplatedViolatedConstraintNameExtracter() {
		@Override
		protected String doExtractConstraintName(final SQLException sqle) throws NumberFormatException {
			final int errorCode = JdbcExceptionHelper.extractErrorCode(sqle) & 0xFF;
			if (errorCode == SQLiteDialect.SQLITE_CONSTRAINT) {
				return extractUsingTemplate("constraint ", " failed", sqle.getMessage());
			}
			return null;
		}
	};

	// union subclass support ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

	@Override
	public boolean supportsUnionAll() {
		return true;
	}

	// DDL support ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

	@Override
	public boolean canCreateSchema() {
		return false;
	}

	@Override
	public boolean hasAlterTable() {
		// As specified in NHibernate dialect
		return false;
	}

	@Override
	public boolean dropConstraints() {
		return false;
	}

	@Override
	public boolean qualifyIndexName() {
		return false;
	}

	@Override
	public String getAddColumnString() {
		return "add column";
	}

	@Override
	public String getDropForeignKeyString() {
		throw new UnsupportedOperationException("No drop foreign key syntax supported by SQLiteDialect");
	}

	@Override
	public String getAddForeignKeyConstraintString(final String constraintName, final String[] foreignKey,
			final String referencedTable, final String[] primaryKey, final boolean referencesPrimaryKey) {
		throw new UnsupportedOperationException("No add foreign key syntax supported by SQLiteDialect");
	}

	@Override
	public String getAddPrimaryKeyConstraintString(final String constraintName) {
		throw new UnsupportedOperationException("No add primary key syntax supported by SQLiteDialect");
	}

	@Override
	public boolean supportsCommentOn() {
		return true;
	}

	@Override
	public boolean supportsIfExistsBeforeTableName() {
		return true;
	}

	/*
	 * not case insensitive for unicode characters by default (ICU extension needed) public boolean
	 * supportsCaseInsensitiveLike() { return true; }
	 */

	@Override
	public boolean doesReadCommittedCauseWritersToBlockReaders() {
		// TODO Validate (WAL mode...)
		return true;
	}

	@Override
	public boolean doesRepeatableReadCauseReadersToBlockWriters() {
		return true;
	}

	@Override
	public boolean supportsTupleDistinctCounts() {
		return false;
	}

	@Override
	public int getInExpressionCountLimit() {
		// Compile/runtime time option: http://sqlite.org/limits.html#max_variable_number
		return 1000;
	}

	@Override
	public UniqueDelegate getUniqueDelegate() {
		return uniqueDelegate;
	}

	private static class SQLiteUniqueDelegate extends DefaultUniqueDelegate {
		public SQLiteUniqueDelegate(final Dialect dialect) {
			super(dialect);
		}

		@Override
		public String getColumnDefinitionUniquenessFragment(final Column column) {
			return " unique";
		}
	}

	@Override
	public String getSelectGUIDString() {
		return "select hex(randomblob(16))";
	}

	@Override
	public ScrollMode defaultScrollMode() {
		return ScrollMode.FORWARD_ONLY;
	}
}